1. Field of the Invention
The present invention relates to a recording apparatus for recording on a recording sheet, and more particularly to such recording apparatus allowing easy setting of the recording sheets.
2. Related Background Art
Among the thermal recording methods currently utilized, there is known a recording method of pressing a thermal recording head to a platen roller across a thermosensitive paper, or an ordinary paper and an ink ribbon. Image recording on the recording sheet is achieved by advancing the thermo-sensitive paper or ordinary paper between the platen roller and the recording head by the rotation of the platen roller and causing the recording head to generate heat in synchronization with the sheet advancement.
In setting of the recording sheet in the apparatus of such recording method, if the recording head and the platen roller are maintained in contact, the recording head is rubbed with the platen roller under friction when it is rotated, thus giving an excessive load on a driving motor for rotating the platen roller and causing unnecessary abrasion of the recording head.
For this reason there has been provided a release lever for releasing the recording head from the platen roller, and the setting of the recording sheet has been achieved by manipulating the release lever to separate the recording head from the platen roller, and rotating the platen roller for example with a manual knob to advance the leading end of the recording sheet to the recording position.
However, in such setting of the recording sheet with the manual knob, the position of leading end of the recording sheet cannot be made constant as it is determined by visual observation.
Some of the recent apparatus are provided with an automatic sheet feeding switch, which, when manipulated, automatically feeds the recording sheet. However, such apparatus is still unsatisfactory in operability, as the operator has to make two operations, namely operation of the release lever and operation of said automatic feeding switch, in the setting of the recording sheet.
For avoiding such drawback, there is also already known an apparatus in which a release lever, for releasing the recording head from the platen roller, is manipulated and locked to maintain the recording head and the platen roller in a separated state, and an automatic feeding switch is then manipulated to automatically feed the recording sheet.
In such structure, however, the operator may forget to return the release lever, after the sheet setting and before the recording operation. In such case the recording operation may be conducted without image formation, as the recording head is not in contact with the recording sheet.
For avoiding such drawback, there is further known an apparatus equipped with a release lever for releasing the recording head from the platen roller, whereby the recording head is separated from the platen roller at the setting of the recording sheet.
In such structure, however, if the released state is eventually cancelled in the course of sheet feeding, there will be generated a sudden change in the load of the motor for driving the platen roller thus disabling exact sheet feeding.